In drilling boreholes for emplacement of measurement or sampling devices, the common practice is to install the desired device in the borehole and then to seal the hole with a grouted liner to fill the entire hole with a sealing material. This limits the use of the hole to that particular sampling or measurement device. Yet another approach is to use a solid casing to support the borehole and then place instrumentation within the casing. The use of the solid casing complicates access of the measurement and sampling devices to the surrounding geologic structure. If instrumentation is included on the casing, the borehole is unsupported and unsealed when the casing is removed for obtaining the collected samples or to change instrumentation.
U.S. Pat. No. 5,176,207, issued Jan. 5, 1993, to Keller, teaches the use of a flexible tubular member to both seal and support a borehole and to carry instrumentation into a borehole as the flexible member is everted into the borehole. Instrumentation and sampling devices can then be placed directly in contact with the surrounding structure. This device provides many improvements in borehole support while obtaining in situ measurements within a borehole. But the everted member must be inverted from within the borehole in order to obtain sample materials collected by the sampling devices or to change measurement instruments placed within the borehole by the everting membrane. When the tubular member is inverted, the borehole is again unsupported and the borehole might then collapse or fill with fluids from the surrounding structure, which tends to intermix the geologic structure and contained fluids so that subsequent sampling and measurements from that borehole will riot provide reliable information.
Accordingly, an object of the present invention is to obtain reliable measurements and sampling from within a borehole while the borehole remains supported and sealed at all times
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.